self-interest vs expedience

self-interest and expedience both are nouns.

Word	Noun	Adjective	Verb	Adverb
self-interest	Yes	No	No	No
expedience	Yes	No	No	No

As nouns, self-interest and expedience are synonyms defined as:

self-interest and expedience: taking advantage of opportunities without regard for the consequences for others

Other synonyms of self-interest include opportunism, self-seeking.

self-interest (noun)	expedience (noun)
concern for your own interests and welfare	the quality of being suited to the end in view
taking advantage of opportunities without regard for the consequences for others	taking advantage of opportunities without regard for the consequences for others